Job 36:1 - Albert Barnes' Notes on the Bible

Elihu also proceeded - Hebrew added - ויסף vayâsaph. Vulgate “addens;” Septuagint, Ηροσθεὶς Eerostheis - “adding, or proceeding.” The Hebrew commentators remark that this word is used because this speech is “added” to the number which it might be supposed he would make. There had been “three” series of speeches, by Job and his friends, and in each one of them Job had spoken three times. Each one of the three friends had also spoken thrice, except Zophar, who failed to reply when it came to his turn. Elihu had also now made three speeches, and here he would naturally have closed, but it is remarked that he “added” this to the usual number.